The video opens with a shot of two jihadis in training. As one absorbs a kick in the stomach, the caption beneath unfurls: "The clatter of war is music to his ears."

Welcome to YouTube - once a playground for teenagers, now an important front in the global war on terror. In recent months footage once available only in Baghdad shops and on jihadi message boards has appeared on video-sharing websites such as YouTube and Google Video.

Some of the videos appear to have been made for propaganda purposes, with Arabic or English subtitles and martial music on the soundtrack. Some show what appear to be the planning stages of an attack: fighters assembling mortars in a room with net curtains, or climbing up a verge with what seems to be an improvised bomb. Others show US soldiers shot dead by insurgent snipers, or Humvees blown up by roadside bombs.

In one video entitled Sniper Hit, a serviceman hit by a sniper gets up to seek cover. Others show soldiers bleeding on the ground. The move marks another evolution for a movement that has been agile in adopting new technology. Chechen mujahadin often do simultaneous releases on their website and YouTube, although most of the videos from Iraq are freelance productions made outside the supervision of the insurgency's propaganda wing, said Josh Devon, a senior analyst at the Site Institute, which monitors extremist websites. "Propaganda for them is paramount," he said. "They realise the powerful effect these videos have - especially on people who are sympathetic. It's a great way for them to communicate with the masses. Without the internet it is very unlikely jihadist groups could command the power that they do."

The migration of such battlefield scenes from obscure jihadi message boards to general interest websites comes amid rising concern that the US is losing ground in the propaganda war against al-Qaida.

Last month the chair of the house intelligence committee, Pete Hoekstra, warned that the West was slow to recognise the importance of propaganda to extremist groups and to counter its effects. "There needs to be an effective complete strategy if we are going to win this war," he told a gathering in Washington.

While television networks generally will use only a quick grab of a jihadist video, websites offer unrestricted access to a potentially global audience of sympathisers. YouTube and Google Video are also a leveller between those who have broadband and parts of the world where slow dial up connections prevail.

"There is definitely an audience in the West that wants to watch this. There are sympathisers all over the place, especially if you are dealing with supporters that don't speak Arabic, or are unable to access English language jihadist message boards," Mr Devon said.

The shelf life of the videos is brief: jihadi films are usually stripped out by YouTube and Google monitors.

The New York Times reported yesterday that more than four dozen combat videos from Iraq had been removed from the sites in recent days. However, others, labelled in Arabic, survived the cull, and new videos are posted every day.